Low complexity transmitter structure for active antenna systems

ABSTRACT

Various embodiments disclosed herein provide for a low complexity transmitter structure for active antenna arrays by reducing the number of digital predistortion extraction loops that need to be performed. Digital predistortion (DPD) corrects any non-linearities in a power amplifier. By determining which power amplifiers have similar characteristics in an array, and thus may use similar predistortion coefficients, once the DPD coefficients are determine for one of the grouped power amplifiers, DPD can be performed on each of the grouped power amplifiers based on the DPD coefficients.

RELATED APPLICATION

The subject patent application is a continuation of, and claims priorityto, U.S. patent application Ser. No. 15/841,245 (now U.S. Pat. No.10,361,733), filed Dec. 13, 2017, and entitled “A LOW COMPLEXITYTRANSMITTER STRUCTURE FOR ACTIVE ANTENNA SYSTEMS,” the entirety of whichapplication is hereby incorporated by reference herein.

TECHNICAL FIELD

The present application relates generally to the field of mobilecommunication and, more specifically, to a low complexity transmitterstructure for active antenna systems.

BACKGROUND

To meet the huge demand for data centric applications, Third GenerationPartnership Project (3GPP) systems and systems that employ one or moreaspects of the specifications of the Fourth Generation (4G) standard forwireless communications will be extended to a Fifth Generation (5G)standard for wireless communications. Unique challenges exist to providelevels of service associated with forthcoming 5G and other nextgeneration network standards.

BRIEF DESCRIPTION OF THE DRAWINGS

Non-limiting and non-exhaustive embodiments of the subject disclosureare described with reference to the following figures, wherein likereference numerals refer to like parts throughout the various viewsunless otherwise specified.

FIG. 1 illustrates an example wireless communication system inaccordance with various aspects and embodiments of the subjectdisclosure.

FIG. 2 illustrates an example block diagram of a group of activeantennas with digital predistortion in accordance with various aspectsand embodiments of the subject disclosure.

FIG. 3 illustrates an example block diagram of a group of activeantennas with digital predistortion in accordance with various aspectsand embodiments of the subject disclosure.

FIG. 4 illustrates an example graph showing power spectral density fordifferent threshold settings in accordance with various aspects andembodiments of the subject disclosure.

FIG. 5 illustrates an example graph showing adjacent channel leakageratios as a function of threshold settings in accordance with variousaspects and embodiments of the subject disclosure.

FIG. 6 illustrates an example block diagram of an active antenna arrayin accordance with various aspects and embodiments of the subjectdisclosure.

FIG. 7 illustrates an example method for providing low complexitydigital predistortion for active antennas in accordance with variousaspects and embodiments of the subject disclosure.

FIG. 8 illustrates an example method for providing low complexitydigital predistortion for active antennas in accordance with variousaspects and embodiments of the subject disclosure.

FIG. 9 illustrates an example block diagram of an example user equipmentthat can be a mobile handset operable to provide a format indicator inaccordance with various aspects and embodiments of the subjectdisclosure.

FIG. 10 illustrates an example block diagram of a computer that can beoperable to execute processes and methods in accordance with variousaspects and embodiments of the subject disclosure.

DETAILED DESCRIPTION

One or more embodiments are now described with reference to thedrawings, wherein like reference numerals are used to refer to likeelements throughout. In the following description, for purposes ofexplanation, numerous specific details are set forth in order to providea thorough understanding of the various embodiments. It is evident,however, that the various embodiments can be practiced without thesespecific details (and without applying to any particular networkedenvironment or standard).

In various embodiments, a transmitter device can comprise a processorand a memory that stores executable instructions that, when executed bythe processor facilitate performance of operations. The operations cancomprise identifying a first digital pre-distortion coefficient of afirst power amplifier. The operations can also comprise identifying asecond digital pre-distortion coefficient of a second power amplifier,wherein the first digital pre-distortion coefficient and the seconddigital pre-distortion coefficient are associated with a first poweramplification nonlinearity associated with the first power amplifier anda second power amplification nonlinearity associated with the secondpower amplifier, respectively. The operations can also comprisedetermining that the first digital pre-distortion coefficient and thesecond digital pre-distortion coefficient are similar according to asimilarity criterion and applying a first pre-distortion signal to thefirst power amplifier and the second power amplifier based on the firstdigital pre-distortion coefficient and the second digital pre-distortioncoefficient.

In another embodiment, method comprises transmitting, by a transmitterdevice comprising a processor, a baseline signal via a group of poweramplifiers associated with respective antennas of an active arrayantenna transmitter. The method can also comprise measuring, by thetransmitter device, outputs of the group of power amplifiers todetermine respective nonlinearities of power amplifiers of the group ofpower amplifiers. The method can also comprise determining, by thetransmitter device, based on the respective nonlinearities, that a firstpower amplifier and a second power amplifier have a first predistortioncoefficient and a second predistortion coefficient respectively that aresimilar according to a similarity criterion, wherein the firstpredistortion coefficient and the second predistortion coefficientrelate to correcting a first nonlinearity associated with the firstpower amplifier and a second nonlinearity associated with the secondpower amplifier. The method can also comprise, based on the firstpredistortion coefficient, applying, by the transmitter device, apredistortion signal to the first power amplifier and the second poweramplifier.

In another embodiment machine-readable storage medium, comprisingexecutable instructions that, when executed by a processor of a device,facilitate performance of operations. The operations can comprisedetermining a first digital pre-distortion coefficient of a first poweramplifier; and determining a second digital pre-distortion coefficientof a second power amplifier, wherein the first digital pre-distortioncoefficient and the second digital pre-distortion coefficient areassociated with power amplifier nonlinearities of the first poweramplifier and the second power amplifier. The operations can alsocomprise determining that the first digital pre-distortion coefficientand the second digital pre-distortion coefficient are similar accordingto a similarity criterion. The operations can also comprise applying afirst pre-distortion signal to the first power amplifier and the secondpower amplifier as a function of the first digital pre-distortioncoefficient and the second digital pre-distortion coefficient.

As used in this disclosure, in some embodiments, the terms “component,”“system” and the like are intended to refer to, or comprise, acomputer-related entity or an entity related to an operational apparatuswith one or more specific functionalities, wherein the entity can beeither hardware, a combination of hardware and software, software, orsoftware in execution. As an example, a component may be, but is notlimited to being, a process running on a processor, a processor, anobject, an executable, a thread of execution, computer-executableinstructions, a program, and/or a computer. By way of illustration andnot limitation, both an application running on a server and the servercan be a component.

One or more components may reside within a process and/or thread ofexecution and a component may be localized on one computer and/ordistributed between two or more computers. In addition, these componentscan execute from various computer readable media having various datastructures stored thereon. The components may communicate via localand/or remote processes such as in accordance with a signal having oneor more data packets (e.g., data from one component interacting withanother component in a local system, distributed system, and/or across anetwork such as the Internet with other systems via the signal). Asanother example, a component can be an apparatus with specificfunctionality provided by mechanical parts operated by electric orelectronic circuitry, which is operated by a software application orfirmware application executed by a processor, wherein the processor canbe internal or external to the apparatus and executes at least a part ofthe software or firmware application. As yet another example, acomponent can be an apparatus that provides specific functionalitythrough electronic components without mechanical parts, the electroniccomponents can comprise a processor therein to execute software orfirmware that confers at least in part the functionality of theelectronic components. While various components have been illustrated asseparate components, it will be appreciated that multiple components canbe implemented as a single component, or a single component can beimplemented as multiple components, without departing from exampleembodiments.

Further, the various embodiments can be implemented as a method,apparatus or article of manufacture using standard programming and/orengineering techniques to produce software, firmware, hardware or anycombination thereof to control a computer to implement the disclosedsubject matter. The term “article of manufacture” as used herein isintended to encompass a computer program accessible from anycomputer-readable (or machine-readable) device or computer-readable (ormachine-readable) storage/communications media. For example, computerreadable storage media can comprise, but are not limited to, magneticstorage devices (e.g., hard disk, floppy disk, magnetic strips), opticaldisks (e.g., compact disk (CD), digital versatile disk (DVD)), smartcards, and flash memory devices (e.g., card, stick, key drive). Ofcourse, those skilled in the art will recognize many modifications canbe made to this configuration without departing from the scope or spiritof the various embodiments.

In addition, the words “example” and “exemplary” are used herein to meanserving as an instance or illustration. Any embodiment or designdescribed herein as “example” or “exemplary” is not necessarily to beconstrued as preferred or advantageous over other embodiments ordesigns. Rather, use of the word example or exemplary is intended topresent concepts in a concrete fashion. As used in this application, theterm “or” is intended to mean an inclusive “or” rather than an exclusive“or”. That is, unless specified otherwise or clear from context, “Xemploys A or B” is intended to mean any of the natural inclusivepermutations. That is, if X employs A; X employs B; or X employs both Aand B, then “X employs A or B” is satisfied under any of the foregoinginstances. In addition, the articles “a” and “an” as used in thisapplication and the appended claims should generally be construed tomean “one or more” unless specified otherwise or clear from context tobe directed to a singular form.

Moreover, terms such as “mobile device equipment,” “mobile station,”“mobile,” “subscriber station,” “access terminal,” “terminal,”“handset,” “communication device,” “mobile device” (and/or termsrepresenting similar terminology) can refer to a wireless deviceutilized by a subscriber or mobile device of a wireless communicationservice to receive or convey data, control, voice, video, sound, gamingor substantially any data-stream or signaling-stream. The foregoingterms are utilized interchangeably herein and with reference to therelated drawings. Likewise, the terms “access point (AP),” “Base Station(BS),” BS transceiver, BS device, cell site, cell site device, “Node B(NB),” “evolved Node B (eNode B),” “home Node B (HNB)” and the like, areutilized interchangeably in the application, and refer to a wirelessnetwork component or appliance that transmits and/or receives data,control, voice, video, sound, gaming or substantially any data-stream orsignaling-stream from one or more subscriber stations. Data andsignaling streams can be packetized or frame-based flows.

Furthermore, the terms “device,” “communication device,” “mobiledevice,” “subscriber,” “customer entity,” “consumer,” “customer entity,”“entity” and the like are employed interchangeably throughout, unlesscontext warrants particular distinctions among the terms. It should beappreciated that such terms can refer to human entities or automatedcomponents supported through artificial intelligence (e.g., a capacityto make inference based on complex mathematical formalisms), which canprovide simulated vision, sound recognition and so forth.

Embodiments described herein can be exploited in substantially anywireless communication technology, comprising, but not limited to,wireless fidelity (Wi-Fi), global system for mobile communications(GSM), universal mobile telecommunications system (UMTS), worldwideinteroperability for microwave access (WiMAX), enhanced general packetradio service (enhanced GPRS), third generation partnership project(3GPP) long term evolution (LTE), third generation partnership project 2(3GPP2) ultra mobile broadband (UMB), high speed packet access (HSPA),Z-Wave, Zigbee and other 802.XX wireless technologies and/or legacytelecommunication technologies.

Various embodiments disclosed herein provide for a low complexitytransmitter structure for active antenna arrays by reducing the numberof digital predistortion extraction loops that need to be performed.Digital predistortion (DPD) corrects any non-linearities in a poweramplifier. By determining which power amplifiers have similarcharacteristics in an array, and thus may use similar predistortioncoefficients, once the DPD coefficients are determine for one of thegrouped power amplifiers, DPD can be performed on each of the groupedpower amplifiers based on the DPD coefficients. DPD extraction can beperformed at regular intervals to ensure that the power amplifiers aregrouped correctly. Over time, and with different environmentalcharacteristics, the non-linearities in the amplifiers can vary, and sothe groupings may change.

The power amplifiers in the active antenna transmitters are determinedto be similar to each other based on sending a baseline signal througheach of the amplifiers and measuring the output. The non-linearities inthe power amplifiers can be judged to be similar to each other if costfunction of the outputs is lower than a predetermined threshold. Ahigher threshold would allow more amplifiers to be grouped together,reducing the complexity, but the digital predistortion performed on eachamplifier may not be as effective as a lower threshold would haveallowed for. Depending on how different the power amplifiernon-linearities are and how many amplifiers there are that need to becorrected, different threshold values can be applied at different times,allowing for a more dynamic solution.

FIG. 1 illustrates an example wireless communication system 100 inaccordance with various aspects and embodiments of the subjectdisclosure. In one or more embodiments, system 100 can comprise one ormore user equipment UEs 104 and 102, which can have one or more antennapanels having vertical and horizontal elements. A UE 102 can be a mobiledevice such as a cellular phone, a smartphone, a tablet computer, awearable device, a virtual reality (VR) device, a heads-up display (HUD)device, a smart car, a machine-type communication (MTC) device, and thelike. User equipment UE 102 can also comprise IOT devices thatcommunicate wirelessly. In various embodiments, system 100 is orcomprises a wireless communication network serviced by one or morewireless communication network providers. In example embodiments, a UE102 can be communicatively coupled to the wireless communication networkvia a network node 106.

The non-limiting term network node (or radio network node) is usedherein to refer to any type of network node serving a UE 102 and UE 104and/or connected to other network node, network element, or anothernetwork node from which the UE 102 or 104 can receive a radio signal.Network nodes can also have multiple antennas for performing varioustransmission operations (e.g., MIMO operations). A network node can havea cabinet and other protected enclosures, an antenna mast, and actualantennas. Network nodes can serve several cells, also called sectors,depending on the configuration and type of antenna. Examples of networknodes (e.g., network node 106) can comprise but are not limited to:NodeB devices, base station (BS) devices, access point (AP) devices, andradio access network (RAN) devices. The network node 106 can alsocomprise multi-standard radio (MSR) radio node devices, including butnot limited to: an MSR BS, an eNode B, a network controller, a radionetwork controller (RNC), a base station controller (BSC), a relay, adonor node controlling relay, a base transceiver station (BTS), atransmission point, a transmission node, an RRU, an RRH, nodes indistributed antenna system (DAS), and the like. In 5G terminology, thenode 106 can be referred to as a gNodeB device.

Wireless communication system 100 can employ various cellulartechnologies and modulation schemes to facilitate wireless radiocommunications between devices (e.g., the UE 102 and 104 and the networknode 106). For example, system 100 can operate in accordance with aUMTS, long term evolution (LTE), high speed packet access (HSPA), codedivision multiple access (CDMA), time division multiple access (TDMA),frequency division multiple access (FDMA), multi-carrier code divisionmultiple access (MC-CDMA), single-carrier code division multiple access(SC-CDMA), single-carrier FDMA (SC-FDMA), OFDM, (DFT)-spread OFDM orSC-FDMA)), FBMC, ZT DFT-s-OFDM, GFDM, UFMC, UW DFT-Spread-OFDM, UW-OFDM,CP-OFDM, resource-block-filtered OFDM, and UFMC. However, variousfeatures and functionalities of system 100 are particularly describedwherein the devices (e.g., the UEs 102 and 104 and the network device106) of system 100 are configured to communicate wireless signals usingone or more multi carrier modulation schemes, wherein data symbols canbe transmitted simultaneously over multiple frequency subcarriers (e.g.,OFDM, CP-OFDM, DFT-spread OFMD, UFMC, FMBC, etc.).

In various embodiments, system 100 can be configured to provide andemploy 5G wireless networking features and functionalities. 5G wirelesscommunication networks are expected to fulfill the demand ofexponentially increasing data traffic and to allow people and machinesto enjoy gigabit data rates with virtually zero latency. Compared to 4G,5G supports more diverse traffic scenarios. For example, in addition tothe various types of data communication between conventional UEs (e.g.,phones, smartphones, tablets, PCs, televisions, Internet enabledtelevisions, etc.) supported by 4G networks, 5G networks can be employedto support data communication between smart cars in association withdriverless car environments, as well as machine type communications(MTCs). Considering the drastic different communication needs of thesedifferent traffic scenarios, the ability to dynamically configurewaveform parameters based on traffic scenarios while retaining thebenefits of multi carrier modulation schemes (e.g., OFDM and relatedschemes) can provide a significant contribution to the highspeed/capacity and low latency demands of 5G networks. With waveformsthat split the bandwidth into several sub-bands, different types ofservices can be accommodated in different sub-bands with the mostsuitable waveform and numerology, leading to an improved spectrumutilization for 5G networks.

It is well known that MIMO systems can significantly increase the datacarrying capacity of wireless systems. For these reasons, MIMO is anintegral part of the 3^(rd) and 4^(th) generation wireless systems. 5Gsystems will also employ MIMO systems also called massive MIMO systems(hundreds of antennas at the Transmitter side and/Receiver side).Typically, with a (N_(t),N_(r)), where N_(t) denotes the number oftransmit antennas and Nr denotes the receive antennas, the peak datarate multiplies with a factor of N_(t) over single antenna systems inrich scattering environment.

MIMO systems can be active array antennas systems where RF componentssuch as power amplifiers and transceivers are integrated with an arrayof antennas elements. By contrast, in passive antennas array systems thebaseband signals are boosted by power amplifiers and connected to theantennas by longer feedback cables. By using active antenna array, notonly are cable losses reduced, leading to improved performance andreduced energy consumption, but also is the installation simplified andthe required equipment space is reduced.

By using respective power amplifiers for each antenna element in anactive array antenna system, power amplifier non-linearities are hard tocorrect for. When power amplifiers operate in the non-linear regions,some of the signals are leaked to the other frequency bands causingadjacent channel interference.

One exemplary method to compensate for the non-linearity of the poweramplifier is to distort the input signal to the power amplifier (PA)such that the output signal from the PA is transformed to be close towhat it would have been if the PA would have been linear. An example ofsuch method is called Digital Pre-distortion (DPD) Technique. Ingeneral, DPD may interchangeably be called as a signal linearizationcircuitry or component or mechanism or scheme.

Let y₁ be the output signal at the output of the PA and let x₁ be theoutput signal from the baseband and z1 is the input signal to the PA.Note that, in this model, we consider only the impact due to nonlinearPA and in practical systems the PA is preceded by many other blocks suchas digital to analog converter (DAC), local oscillator (LO) etc. Theoutput signal can be expressed as y₁=f₁(z₁) where f₁ (.) is a nonlinearfunction which characterizes the PA. With DPD, the above equations canbe written as y₂=f₁(g₁(x₁)), where g1(.) is the function whichcharacterizes the DPD block. Note that DPD extraction block is chosensuch that y₂=f₁(g₁(x₁))=G₁·x₁, Where G1 is the gain of PA. It can beseen from above equation that if g1 is properly chosen then the outputof the PA is linear. If there are many power amplifiers, to individuallycorrect for each power amplifier can be a complex and computationallyintensive process. By grouping power amplifiers that have similar DPDcoefficients together however, the same predistortion signal can beapplied to each, resulting in a satisfactory correction and reducingadjacent channel interference while reducing the complexity.

Turning now to FIG. 2, illustrated is an example block diagram 200 of agroup of active antennas with digital predistortion in accordance withvarious aspects and embodiments of the subject disclosure.

Antennas 210 and 220 can each have a DPD extraction component 208 and218 that samples the output of a power amplifier 206 and 216 to modelthe nonlinearities of the PAs 206 and 216. Once the nonlinearities areknown, and the DPD coefficients can be determined, the DPD components204 and 214 will apply a signal to baseband signals 202 and 212 beforethe power amplifier, such that the PAs' 206 and 216 output will becorrected to make the nonlinear aspects of the PAs 206 and 216 performlinearly.

In traditional DPD for an active antenna system, each of the DPDextraction blocks 208 and 218 are operating continuously, determiningDPD coefficients and applying the DPD signal to the baseband signals 202and 212 on a continual basis. These operations require a lot ofcomputational resources and power consumption. In a massive MIMO systemor in system with many transmit antennas (antenna elements), running aDPD loop for all the antenna elements is cumbersome and drains powerresources rapidly, resulting in lower battery life for mobile devices.

According to an embodiment however, if the DPD extraction 218 determinesthat power amplifier 216 has a similar non-linearity as power amplifier206, then it is possible for DPD block 214 to just apply the same DPDsignal to baseband signal 212 as DPD block 204 applies to basebandsignal 202. Applying the same correction to antenna 220, can result inan acceptable reduction in adjacent channel interference due to antenna220's output while skipping the need to computationally determine theDPD coefficients for power amplifier 216.

In an embodiment, the DPD extractions 208 and 218 can sample the poweramplifier non-linearities at defined periods or based on changingconditions. For instance, if the temperature changes more than apredetermined range of degrees, the power amplifier groupings can bepredetermined as the nonlinearities may change, being a function oftemperature.

In FIG. 3, embodiment 300 shows an exemplary active antenna system withfour antennas, 302, 304, 306, and 308. The power amplifiers for antenna302, 306, and 308 have been determined to have non-linearities that aresimilar enough that the same DPD correction applied to antenna 302 cansimilarly be applied to antennas 306 and 308, while antenna 304independent determines DPD coefficients since the non linearities forthe power amplifier to antenna 304 are different than they are forantennas 302, 306, and 308.

Let x₁, x₂, x₃, and x₄ be the output signals from the baseband forrespective antennas 302, 304, 306, and 308 and z₁, z₂, z₃ and z₄ be theinput signal to each PA for respective antennas 302, 304, 306, and 308.The output signal can be expressed as

y₁ = f₁(z ₁), y₂ = f₂(z ₂), y₃ = f₃(z ₃), y₄ = f₄(z ₄)

Where f1 (.), f2 (.), f3 (.) and f4 (.) are nonlinear functions whichcharacterizes the individual PAs. With DPD, the above equations can bewritten as

y 1 = f 1 (g 1(x 1)), y 2 = f 2 (g 2(x 2)), y 3 = f 3 (g 3(x 3)), y 4 = f 4(g 4(x 4))

Where g1(.), g2(.), g3(.) and g4(.) are the functions whichcharacterizes the individual DPD blocks. Note that DPD extraction blocksare chosen such that

y 1 = f 1 (g 1(x 1)) = G 1 ⋅ x 1, y 2 = f 2 (g 2(x 2)) = G 2 ⋅ x 2y 3 = f 3 (g 3(x 3)) = G 3 ⋅ x 3 y 4 = f 4(g 4(x 4)) = G 4 ⋅ x 4

Where G1, G2, G3 and G4 are the individual gains of each PA. It can beseen from above equations that if g1, g2, g3 and g4 are properly chosen,then the outputs of the PAs are linear and the emissions will be less.

In the embodiment shown in FIG. 3, when f1(.) (antenna 302) isapproximately equal to that of f3 (.)(antenna 306) and f4 (.)(antenna308), then the above equation can be written as

y 1 = f 1 (g 1(x 1)) = G 1 ⋅ x 1, y 2 = f 2 (g 2(x 2)) = G 2 ⋅ x 2y 3 = f 3 (g 1(x 3)) ≅ G 3 ⋅ x 3 y 4 = f 4(g 1(x 4)) ≅ G 4 ⋅ x 4.

In an embodiment, the non-linearities can be determined by passing aknown baseline signal through each of the power amplifiers and examiningthe output of the power amplifiers to model the non-linearities. Usingthe embodiment in FIG. 3 as an example, for grouping, the same signalsays x is transmitted from all the PAs. Say the output of the PA isgiven by f1(x), f2(x), f3(x) and f4(x) are the output signals from eachPA associated with antennas 302, 304, 306, and 308. Then we need toidentify which among them 4 are almost identical. Let's define the costfunction of for comparison between two outputs asJ=(fi(x)−fj(x))*(fi(x)−fj(x))^(H) where i and j are from 1 to 4. Basedon the PAs, i and j are grouped if J≤Jth. Jth is a predefined threshold,and as can be seen from the equation, the range of similarity is largeras Jth increases. Thus, for a small Jth, power amplifiers are not aslikely to be grouped together, resulting in lower adjacent channelinterference, but increased computational costs and power consumption,while for a larger Jth, the computational costs and power consumptionmay be reduced greatly, but there may be increased adjacent channelinterference.

The threshold for grouping power amplifiers can thus be dynamicallyadjusted depending on various conditions, as long as the adjacentchannel leakage ratio stays below a predetermined threshold (e.g., belowa 3GPP defined threshold). Non-linearities in power amplifiers canchange as a function of time, age, temperature, and other environmentalconditions. Accordingly, an acceptable level of adjacent channelinterference at a higher Jth threshold at one time, may result inincreased adjacent channel interference at the same Jth threshold atanother time, and so the Jth threshold can be reduced to account for thechanging conditions. These settings can also be adjusted by a degreebased on changing user settings. For instance, if a mobile device with aMIMO transmitter is low on battery, or the user selects a battery savingmode, a higher Jth threshold can be selected for the mobile device.Similarly, if there is a large amount of interference, and or low signalto noise ratio for transmissions between the transmitter and receiver,the transmitter can reduce the threshold to decrease the adjacentchannel interference.

Turning now to FIG. 4, illustrated is an example graph 400 showing powerspectral density for different threshold settings in accordance withvarious aspects and embodiments of the subject disclosure. Line 410 canrepresent an ideal power amplifier output, with a peak at the selectedfrequency. Uncorrected power amplifiers can have high power densities atfrequencies outside of the selected frequency due to the non-linearitiesof the power amplifiers. The DPD process lowers the amount of powerdensity in the areas outside the channel by partially correcting for thenon-linearities.

Graph 400 shows the simulator results showing power amplifier leakage atdifferent Jth thresholds. Line 402 shows the performance where the Jththreshold is set to 25. But at lines 404, 406, and 408, representing aJth threshold of 2.5, 0.5, and 0.0 respectively, the power leakageoutside the band has been greatly reduced. In fact, there is very littlebenefit, at this particular time of selecting a Jth threshold of 0.0over a Jth threshold of 2.5 as can be seen. The Jth threshold of 2.5 isa large improvement over the Jth threshold of 25, but there arediminishing returns to selecting a Jth threshold lower than 2.5. Atanother time though, the power density distribution can be different,and so the Jth threshold can be dynamically set to account for changingconditions, non-linearities, etc.

Turning now to FIG. 5, illustrated is an example graph 500 showingadjacent channel leakage ratios (ACLR) as a function of thresholdsettings in accordance with various aspects and embodiments of thesubject disclosure. As the line 502 shows, as Jth increases, the ACLRincreases proportionally.

FIG. 6, illustrated is an example block diagram 600 of an active antennaarray 602 in accordance with various aspects and embodiments of thesubject disclosure.

Active antenna array 602 can include a measurement component 604 thatmeasures and determines the non-linearities in each of the poweramplifiers in the active antenna array 602. In an embodiment, themeasurement component 604 can determine the non-linearities based onsending a known baseline signal through each of the power amplifiers andmeasuring the output.

The active antenna array 602 can also include a grouping component 606that groups the power amplifiers based on their degrees of similarity.The degree of similarity can be based on cost function that measures therelative differences between the power amplifiers. The cost function forcomparison between two outputs can be J=(fi(x)−fj(x))*(fi(x)−fj(x))^(H)where i and j represent any two different power amplifiers. Based on thePAs, i and j are grouped if J≤Jth. Jth is a predefined threshold, and ascan be seen from the equation, the range of similarity is larger as Jthincreases. Thus, for a small Jth, power amplifiers are not as likely tobe grouped together, resulting in lower adjacent channel interference,but increased computational costs and power consumption, while for alarger Jth, the computational costs and power consumption may be reducedgreatly, but there may be increased adjacent channel interference.

Active antenna array 602 can also include a predistorter component 608that applies a DPD signal to a baseband signal to correct for thenonlinearity in a power amplifier. The DPD signal can be applied beforethe power amplifier amplifies the baseband signal.

The active antenna array 602 can also include a threshold component 610that can adjust the Jth threshold depending on current conditions. In anembodiment, threshold component 610 can adjust the Jth threshold to beas high as possible, while still enabling the adjacent channelinterference to meet 3GPP and other predefined standards. In otherembodiments, the threshold component 610 can select the Jth threshold onuser preferences, selection, and/or other criteria.

FIGS. 7-8 illustrates a process in connection with the aforementionedsystems. The processes in FIGS. 7-8 can be implemented for example bythe systems in FIGS. 1-6 respectively. While for purposes of simplicityof explanation, the methods are shown and described as a series ofblocks, it is to be understood and appreciated that the claimed subjectmatter is not limited by the order of the blocks, as some blocks mayoccur in different orders and/or concurrently with other blocks fromwhat is depicted and described herein. Moreover, not all illustratedblocks may be required to implement the methods described hereinafter.

FIG. 7 illustrates an example method 700 for providing low complexitydigital predistortion for active antennas in accordance with variousaspects and embodiments of the subject disclosure.

Method 700 can start at 702, where the method comprises identifying afirst digital pre-distortion coefficient of a first power amplifier.

At 704 the method comprises identifying a second digital pre-distortioncoefficient of a second power amplifier, wherein the first digitalpre-distortion coefficient and the second digital pre-distortioncoefficient are associated with a first power amplification nonlinearityassociated with the first power amplifier and a second poweramplification nonlinearity associated with the second power amplifier,respectively.

At 706, the method comprises determining that the first digitalpre-distortion coefficient and the second digital pre-distortioncoefficient are similar according to a similarity criterion.

At 708, the method comprises applying a first pre-distortion signal tothe first power amplifier and the second power amplifier based on thefirst digital pre-distortion coefficient and the second digitalpre-distortion coefficient.

FIG. 8 illustrates an example method 800 for providing low complexitydigital predistortion for active antennas in accordance with variousaspects and embodiments of the subject disclosure.

Method 800 can start at 802, where the method comprises transmitting, bya transmitter device comprising a processor, a baseline signal via agroup of power amplifiers associated with respective antennas of anactive array antenna transmitter.

At 804 the method comprises measuring, by the transmitter device,outputs of the group of power amplifiers to determine respectivenonlinearities of power amplifiers of the group of power amplifiers.

At 806, the method comprises determining, by the transmitter device,based on the respective nonlinearities, that a first power amplifier anda second power amplifier have a first predistortion coefficient and asecond predistortion coefficient respectively that are similar accordingto a similarity criterion, wherein the first predistortion coefficientand the second predistortion coefficient relate to correcting a firstnonlinearity associated with the first power amplifier and a secondnonlinearity associated with the second power amplifier.

At 808, the method comprises based on the first predistortioncoefficient, applying, by the transmitter device, a predistortion signalto the first power amplifier and the second power amplifier.

Referring now to FIG. 9, illustrated is a schematic block diagram of anexample end-user device such as a user equipment) that can be a mobiledevice 900 capable of connecting to a network in accordance with someembodiments described herein. Although a mobile handset 900 isillustrated herein, it will be understood that other devices can be amobile device, and that the mobile handset 900 is merely illustrated toprovide context for the embodiments of the various embodiments describedherein. The following discussion is intended to provide a brief, generaldescription of an example of a suitable environment 900 in which thevarious embodiments can be implemented. While the description includes ageneral context of computer-executable instructions embodied on amachine-readable storage medium, those skilled in the art will recognizethat the various embodiments also can be implemented in combination withother program modules and/or as a combination of hardware and software.

Generally, applications (e.g., program modules) can include routines,programs, components, data structures, etc., that perform particulartasks or implement particular abstract data types. Moreover, thoseskilled in the art will appreciate that the methods described herein canbe practiced with other system configurations, includingsingle-processor or multiprocessor systems, minicomputers, mainframecomputers, as well as personal computers, hand-held computing devices,microprocessor-based or programmable consumer electronics, and the like,each of which can be operatively coupled to one or more associateddevices.

A computing device can typically include a variety of machine-readablemedia. Machine-readable media can be any available media that can beaccessed by the computer and includes both volatile and non-volatilemedia, removable and non-removable media. By way of example and notlimitation, computer-readable media can comprise computer storage mediaand communication media. Computer storage media can include volatileand/or non-volatile media, removable and/or non-removable mediaimplemented in any method or technology for storage of information, suchas computer-readable instructions, data structures, program modules orother data. Computer storage media can include, but is not limited to,RAM, ROM, EEPROM, flash memory or other memory technology, CD ROM,digital video disk (DVD) or other optical disk storage, magneticcassettes, magnetic tape, magnetic disk storage or other magneticstorage devices, or any other medium which can be used to store thedesired information and which can be accessed by the computer.

Communication media typically embodies computer-readable instructions,data structures, program modules or other data in a modulated datasignal such as a carrier wave or other transport mechanism, and includesany information delivery media. The term “modulated data signal” means asignal that has one or more of its characteristics set or changed insuch a manner as to encode information in the signal. By way of example,and not limitation, communication media includes wired media such as awired network or direct-wired connection, and wireless media such asacoustic, RF, infrared and other wireless media. Combinations of the anyof the above should also be included within the scope ofcomputer-readable media.

The handset 900 includes a processor 902 for controlling and processingall onboard operations and functions. A memory 904 interfaces to theprocessor 902 for storage of data and one or more applications 906(e.g., a video player software, user feedback component software, etc.).Other applications can include voice recognition of predetermined voicecommands that facilitate initiation of the user feedback signals. Theapplications 906 can be stored in the memory 904 and/or in a firmware908, and executed by the processor 902 from either or both the memory904 or/and the firmware 908. The firmware 908 can also store startupcode for execution in initializing the handset 900. A communicationscomponent 910 interfaces to the processor 902 to facilitatewired/wireless communication with external systems, e.g., cellularnetworks, VoIP networks, and so on. Here, the communications component910 can also include a suitable cellular transceiver 911 (e.g., a GSMtransceiver) and/or an unlicensed transceiver 913 (e.g., Wi-Fi, WiMax)for corresponding signal communications. The handset 900 can be a devicesuch as a cellular telephone, a PDA with mobile communicationscapabilities, and messaging-centric devices. The communicationscomponent 910 also facilitates communications reception from terrestrialradio networks (e.g., broadcast), digital satellite radio networks, andInternet-based radio services networks.

The handset 900 includes a display 912 for displaying text, images,video, telephony functions (e.g., a Caller ID function), setupfunctions, and for user input. For example, the display 912 can also bereferred to as a “screen” that can accommodate the presentation ofmultimedia content (e.g., music metadata, messages, wallpaper, graphics,etc.). The display 912 can also display videos and can facilitate thegeneration, editing and sharing of video quotes. A serial I/O interface914 is provided in communication with the processor 902 to facilitatewired and/or wireless serial communications (e.g., USB, and/or IEEE1394) through a hardwire connection, and other serial input devices(e.g., a keyboard, keypad, and mouse). This supports updating andtroubleshooting the handset 900, for example. Audio capabilities areprovided with an audio I/O component 916, which can include a speakerfor the output of audio signals related to, for example, indication thatthe user pressed the proper key or key combination to initiate the userfeedback signal. The audio I/O component 916 also facilitates the inputof audio signals through a microphone to record data and/or telephonyvoice data, and for inputting voice signals for telephone conversations.

The handset 900 can include a slot interface 918 for accommodating a SIC(Subscriber Identity Component) in the form factor of a card SubscriberIdentity Module (SIM) or universal SIM 920, and interfacing the SIM card920 with the processor 902. However, it is to be appreciated that theSIM card 920 can be manufactured into the handset 900, and updated bydownloading data and software.

The handset 900 can process IP data traffic through the communicationcomponent 910 to accommodate IP traffic from an IP network such as, forexample, the Internet, a corporate intranet, a home network, a personarea network, etc., through an ISP or broadband cable provider. Thus,VoIP traffic can be utilized by the handset 800 and IP-based multimediacontent can be received in either an encoded or decoded format.

A video processing component 922 (e.g., a camera) can be provided fordecoding encoded multimedia content. The video processing component 922can aid in facilitating the generation, editing and sharing of videoquotes. The handset 900 also includes a power source 924 in the form ofbatteries and/or an AC power subsystem, which power source 924 caninterface to an external power system or charging equipment (not shown)by a power I/O component 926.

The handset 900 can also include a video component 930 for processingvideo content received and, for recording and transmitting videocontent. For example, the video component 930 can facilitate thegeneration, editing and sharing of video quotes. A location trackingcomponent 932 facilitates geographically locating the handset 900. Asdescribed hereinabove, this can occur when the user initiates thefeedback signal automatically or manually. A user input component 934facilitates the user initiating the quality feedback signal. The userinput component 934 can also facilitate the generation, editing andsharing of video quotes. The user input component 934 can include suchconventional input device technologies such as a keypad, keyboard,mouse, stylus pen, and/or touch screen, for example.

Referring again to the applications 906, a hysteresis component 936facilitates the analysis and processing of hysteresis data, which isutilized to determine when to associate with the access point. Asoftware trigger component 938 can be provided that facilitatestriggering of the hysteresis component 938 when the Wi-Fi transceiver913 detects the beacon of the access point. A SIP client 940 enables thehandset 900 to support SIP protocols and register the subscriber withthe SIP registrar server. The applications 906 can also include a client942 that provides at least the capability of discovery, play and storeof multimedia content, for example, music.

The handset 900, as indicated above related to the communicationscomponent 810, includes an indoor network radio transceiver 913 (e.g.,Wi-Fi transceiver). This function supports the indoor radio link, suchas IEEE 802.11, for the dual-mode GSM handset 900. The handset 900 canaccommodate at least satellite radio services through a handset that cancombine wireless voice and digital radio chipsets into a single handhelddevice.

Referring now to FIG. 10, there is illustrated a block diagram of acomputer 1000 operable to execute the functions and operations performedin the described example embodiments. For example, a network node (e.g.,network node 406) may contain components as described in FIG. 10. Thecomputer 1000 can provide networking and communication capabilitiesbetween a wired or wireless communication network and a server and/orcommunication device. In order to provide additional context for variousaspects thereof, FIG. 10 and the following discussion are intended toprovide a brief, general description of a suitable computing environmentin which the various aspects of the embodiments can be implemented tofacilitate the establishment of a transaction between an entity and athird party. While the description above is in the general context ofcomputer-executable instructions that can run on one or more computers,those skilled in the art will recognize that the various embodimentsalso can be implemented in combination with other program modules and/oras a combination of hardware and software.

Generally, program modules include routines, programs, components, datastructures, etc., that perform particular tasks or implement particularabstract data types. Moreover, those skilled in the art will appreciatethat the inventive methods can be practiced with other computer systemconfigurations, including single-processor or multiprocessor computersystems, minicomputers, mainframe computers, as well as personalcomputers, hand-held computing devices, microprocessor-based orprogrammable consumer electronics, and the like, each of which can beoperatively coupled to one or more associated devices.

The illustrated aspects of the various embodiments can also be practicedin distributed computing environments where certain tasks are performedby remote processing devices that are linked through a communicationsnetwork. In a distributed computing environment, program modules can belocated in both local and remote memory storage devices.

Computing devices typically include a variety of media, which caninclude computer-readable storage media or communications media, whichtwo terms are used herein differently from one another as follows.

Computer-readable storage media can be any available storage media thatcan be accessed by the computer and includes both volatile andnonvolatile media, removable and non-removable media. By way of example,and not limitation, computer-readable storage media can be implementedin connection with any method or technology for storage of informationsuch as computer-readable instructions, program modules, structureddata, or unstructured data. Computer-readable storage media can include,but are not limited to, RAM, ROM, EEPROM, flash memory or other memorytechnology, CD-ROM, digital versatile disk (DVD) or other optical diskstorage, magnetic cassettes, magnetic tape, magnetic disk storage orother magnetic storage devices, or other tangible and/or non-transitorymedia which can be used to store desired information. Computer-readablestorage media can be accessed by one or more local or remote computingdevices, e.g., via access requests, queries or other data retrievalprotocols, for a variety of operations with respect to the informationstored by the medium.

Communications media can embody computer-readable instructions, datastructures, program modules or other structured or unstructured data ina data signal such as a modulated data signal, e.g., a carrier wave orother transport mechanism, and includes any information delivery ortransport media. The term “modulated data signal” or signals refers to asignal that has one or more of its characteristics set or changed insuch a manner as to encode information in one or more signals. By way ofexample, and not limitation, communication media include wired media,such as a wired network or direct-wired connection, and wireless mediasuch as acoustic, RF, infrared and other wireless media.

With reference to FIG. 10, implementing various aspects described hereinwith regards to the end-user device can include a computer 1000, thecomputer 1000 including a processing unit 1004, a system memory 1006 anda system bus 1008. The system bus 1008 couples system componentsincluding, but not limited to, the system memory 1006 to the processingunit 1004. The processing unit 1004 can be any of various commerciallyavailable processors. Dual microprocessors and other multi-processorarchitectures can also be employed as the processing unit 1004.

The system bus 1008 can be any of several types of bus structure thatcan further interconnect to a memory bus (with or without a memorycontroller), a peripheral bus, and a local bus using any of a variety ofcommercially available bus architectures. The system memory 1006includes read-only memory (ROM) 1027 and random access memory (RAM)1012. A basic input/output system (BIOS) is stored in a non-volatilememory 1027 such as ROM, EPROM, EEPROM, which BIOS contains the basicroutines that help to transfer information between elements within thecomputer 1000, such as during start-up. The RAM 1012 can also include ahigh-speed RAM such as static RAM for caching data.

The computer 1000 further includes an internal hard disk drive (HDD)1014 (e.g., EIDE, SATA), which internal hard disk drive 1014 can also beconfigured for external use in a suitable chassis (not shown), amagnetic floppy disk drive (FDD) 1016, (e.g., to read from or write to aremovable diskette 1018) and an optical disk drive 1020, (e.g., readinga CD-ROM disk 1022 or, to read from or write to other high capacityoptical media such as the DVD). The hard disk drive 1014, magnetic diskdrive 1016 and optical disk drive 1020 can be connected to the systembus 1008 by a hard disk drive interface 1024, a magnetic disk driveinterface 1026 and an optical drive interface 1028, respectively. Theinterface 1024 for external drive implementations includes at least oneor both of Universal Serial Bus (USB) and IEEE 1394 interfacetechnologies. Other external drive connection technologies are withincontemplation of the subject embodiments.

The drives and their associated computer-readable media providenonvolatile storage of data, data structures, computer-executableinstructions, and so forth. For the computer 1000 the drives and mediaaccommodate the storage of any data in a suitable digital format.Although the description of computer-readable media above refers to aHDD, a removable magnetic diskette, and a removable optical media suchas a CD or DVD, it should be appreciated by those skilled in the artthat other types of media which are readable by a computer 1000, such aszip drives, magnetic cassettes, flash memory cards, cartridges, and thelike, can also be used in the example operating environment, andfurther, that any such media can contain computer-executableinstructions for performing the methods of the disclosed embodiments.

A number of program modules can be stored in the drives and RAM 1012,including an operating system 1030, one or more application programs1032, other program modules 1034 and program data 1036. All or portionsof the operating system, applications, modules, and/or data can also becached in the RAM 1012. It is to be appreciated that the variousembodiments can be implemented with various commercially availableoperating systems or combinations of operating systems.

A user can enter commands and information into the computer 1000 throughone or more wired/wireless input devices, e.g., a keyboard 1038 and apointing device, such as a mouse 1040. Other input devices (not shown)may include a microphone, an IR remote control, a joystick, a game pad,a stylus pen, touch screen, or the like. These and other input devicesare often connected to the processing unit 1004 through an input deviceinterface 1042 that is coupled to the system bus 1008, but can beconnected by other interfaces, such as a parallel port, an IEEE 1394serial port, a game port, a USB port, an IR interface, etc.

A monitor 1044 or other type of display device is also connected to thesystem bus 1008 through an interface, such as a video adapter 1046. Inaddition to the monitor 1044, a computer 1000 typically includes otherperipheral output devices (not shown), such as speakers, printers, etc.

The computer 1000 can operate in a networked environment using logicalconnections by wired and/or wireless communications to one or moreremote computers, such as a remote computer(s) 1048. The remotecomputer(s) 1048 can be a workstation, a server computer, a router, apersonal computer, portable computer, microprocessor-based entertainmentdevice, a peer device or other common network node, and typicallyincludes many or all of the elements described relative to the computer,although, for purposes of brevity, only a memory/storage device 1050 isillustrated. The logical connections depicted include wired/wirelessconnectivity to a local area network (LAN) 1052 and/or larger networks,e.g., a wide area network (WAN) 1054. Such LAN and WAN networkingenvironments are commonplace in offices and companies, and facilitateenterprise-wide computer networks, such as intranets, all of which mayconnect to a global communications network, e.g., the Internet.

When used in a LAN networking environment, the computer 1000 isconnected to the local network 1052 through a wired and/or wirelesscommunication network interface or adapter 1056. The adapter 1056 mayfacilitate wired or wireless communication to the LAN 1052, which mayalso include a wireless access point disposed thereon for communicatingwith the wireless adapter 1056.

When used in a WAN networking environment, the computer 1000 can includea modem 1058, or is connected to a communications server on the WAN1054, or has other means for establishing communications over the WAN1054, such as by way of the Internet. The modem 1058, which can beinternal or external and a wired or wireless device, is connected to thesystem bus 1008 through the input device interface 1042. In a networkedenvironment, program modules depicted relative to the computer, orportions thereof, can be stored in the remote memory/storage device1050. It will be appreciated that the network connections shown areexemplary and other means of establishing a communications link betweenthe computers can be used.

The computer is operable to communicate with any wireless devices orentities operatively disposed in wireless communication, e.g., aprinter, scanner, desktop and/or portable computer, portable dataassistant, communications satellite, any piece of equipment or locationassociated with a wirelessly detectable tag (e.g., a kiosk, news stand,restroom), and telephone. This includes at least Wi-Fi and Bluetooth™wireless technologies. Thus, the communication can be a predefinedstructure as with a conventional network or simply an ad hoccommunication between at least two devices.

Wi-Fi, or Wireless Fidelity, allows connection to the Internet from acouch at home, a bed in a hotel room, or a conference room at work,without wires. Wi-Fi is a wireless technology similar to that used in acell phone that enables such devices, e.g., computers, to send andreceive data indoors and out; anywhere within the range of a basestation. Wi-Fi networks use radio technologies called IEEE802.11 (a, b,g, n, etc.) to provide secure, reliable, fast wireless connectivity. AWi-Fi network can be used to connect computers to each other, to theInternet, and to wired networks (which use IEEE802.3 or Ethernet). Wi-Finetworks operate in the unlicensed 2.4 and 5 GHz radio bands, at an 11Mbps (802.11b) or 54 Mbps (802.11a) data rate, for example, or withproducts that contain both bands (dual band), so the networks canprovide real-world performance similar to the basic “10BaseT” wiredEthernet networks used in many offices.

As used in this application, the terms “system,” “component,”“interface,” and the like are generally intended to refer to acomputer-related entity or an entity related to an operational machinewith one or more specific functionalities. The entities disclosed hereincan be either hardware, a combination of hardware and software,software, or software in execution. For example, a component may be, butis not limited to being, a process running on a processor, a processor,an object, an executable, a thread of execution, a program, and/or acomputer. By way of illustration, both an application running on aserver and the server can be a component. One or more components mayreside within a process and/or thread of execution and a component maybe localized on one computer and/or distributed between two or morecomputers. These components also can execute from various computerreadable storage media having various data structures stored thereon.The components may communicate via local and/or remote processes such asin accordance with a signal having one or more data packets (e.g., datafrom one component interacting with another component in a local system,distributed system, and/or across a network such as the Internet withother systems via the signal). As another example, a component can be anapparatus with specific functionality provided by mechanical partsoperated by electric or electronic circuitry that is operated bysoftware or firmware application(s) executed by a processor, wherein theprocessor can be internal or external to the apparatus and executes atleast a part of the software or firmware application. As yet anotherexample, a component can be an apparatus that provides specificfunctionality through electronic components without mechanical parts,the electronic components can comprise a processor therein to executesoftware or firmware that confers at least in part the functionality ofthe electronic components. An interface can comprise input/output (I/O)components as well as associated processor, application, and/or APIcomponents.

Furthermore, the disclosed subject matter may be implemented as amethod, apparatus, or article of manufacture using standard programmingand/or engineering techniques to produce software, firmware, hardware,or any combination thereof to control a computer to implement thedisclosed subject matter. The term “article of manufacture” as usedherein is intended to encompass a computer program accessible from anycomputer-readable device, computer-readable carrier, orcomputer-readable media. For example, computer-readable media caninclude, but are not limited to, a magnetic storage device, e.g., harddisk; floppy disk; magnetic strip(s); an optical disk (e.g., compactdisk (CD), a digital video disc (DVD), a Blu-ray Disc™ (BD)); a smartcard; a flash memory device (e.g., card, stick, key drive); and/or avirtual device that emulates a storage device and/or any of the abovecomputer-readable media.

As it employed in the subject specification, the term “processor” canrefer to substantially any computing processing unit or devicecomprising, but not limited to comprising, single-core processors;single-processors with software multithread execution capability;multi-core processors; multi-core processors with software multithreadexecution capability; multi-core processors with hardware multithreadtechnology; parallel platforms; and parallel platforms with distributedshared memory. Additionally, a processor can refer to an integratedcircuit, an application specific integrated circuit (ASIC), a digitalsignal processor (DSP), a field programmable gate array (FPGA), aprogrammable logic controller (PLC), a complex programmable logic device(CPLD), a discrete gate or transistor logic, discrete hardwarecomponents, or any combination thereof designed to perform the functionsdescribed herein. Processors can exploit nano-scale architectures suchas, but not limited to, molecular and quantum-dot based transistors,switches and gates, in order to optimize space usage or enhanceperformance of user equipment. A processor also can be implemented as acombination of computing processing units.

In the subject specification, terms such as “store,” “data store,” “datastorage,” “database,” “repository,” “queue”, and substantially any otherinformation storage component relevant to operation and functionality ofa component, refer to “memory components,” or entities embodied in a“memory” or components comprising the memory. It will be appreciatedthat the memory components described herein can be either volatilememory or nonvolatile memory, or can comprise both volatile andnonvolatile memory. In addition, memory components or memory elementscan be removable or stationary. Moreover, memory can be internal orexternal to a device or component, or removable or stationary. Memorycan comprise various types of media that are readable by a computer,such as hard-disc drives, zip drives, magnetic cassettes, flash memorycards or other types of memory cards, cartridges, or the like.

By way of illustration, and not limitation, nonvolatile memory cancomprise read only memory (ROM), programmable ROM (PROM), electricallyprogrammable ROM (EPROM), electrically erasable ROM (EEPROM), or flashmemory. Volatile memory can comprise random access memory (RAM), whichacts as external cache memory. By way of illustration and notlimitation, RAM is available in many forms such as synchronous RAM(SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rateSDRAM (DDR SDRAM), enhanced SDRAM (ESDRAM), Synchlink DRAM (SLDRAM), anddirect Rambus RAM (DRRAM). Additionally, the disclosed memory componentsof systems or methods herein are intended to comprise, without beinglimited to comprising, these and any other suitable types of memory.

In particular and in regard to the various functions performed by theabove described components, devices, circuits, systems and the like, theterms (including a reference to a “means”) used to describe suchcomponents are intended to correspond, unless otherwise indicated, toany component which performs the specified function of the describedcomponent (e.g., a functional equivalent), even though not structurallyequivalent to the disclosed structure, which performs the function inthe herein illustrated example aspects of the embodiments. In thisregard, it will also be recognized that the embodiments comprises asystem as well as a computer-readable medium having computer-executableinstructions for performing the acts and/or events of the variousmethods.

Computing devices typically comprise a variety of media, which cancomprise computer-readable storage media and/or communications media,which two terms are used herein differently from one another as follows.Computer-readable storage media can be any available storage media thatcan be accessed by the computer and comprises both volatile andnonvolatile media, removable and non-removable media. By way of example,and not limitation, computer-readable storage media can be implementedin connection with any method or technology for storage of informationsuch as computer-readable instructions, program modules, structureddata, or unstructured data. Computer-readable storage media cancomprise, but are not limited to, RAM, ROM, EEPROM, flash memory orother memory technology, CD-ROM, digital versatile disk (DVD) or otheroptical disk storage, magnetic cassettes, magnetic tape, magnetic diskstorage or other magnetic storage devices, or other tangible and/ornon-transitory media which can be used to store desired information.Computer-readable storage media can be accessed by one or more local orremote computing devices, e.g., via access requests, queries or otherdata retrieval protocols, for a variety of operations with respect tothe information stored by the medium.

On the other hand, communications media typically embodycomputer-readable instructions, data structures, program modules orother structured or unstructured data in a data signal such as amodulated data signal, e.g., a carrier wave or other transportmechanism, and comprises any information delivery or transport media.The term “modulated data signal” or signals refers to a signal that hasone or more of its characteristics set or changed in such a manner as toencode information in one or more signals. By way of example, and notlimitation, communications media comprise wired media, such as a wirednetwork or direct-wired connection, and wireless media such as acoustic,RF, infrared and other wireless media

Further, terms like “user equipment,” “user device,” “mobile device,”“mobile,” “station,” “access terminal,” “terminal,” “handset,” andsimilar terminology, generally refer to a wireless device utilized by asubscriber or user of a wireless communication network or service toreceive or convey data, control, voice, video, sound, gaming, orsubstantially any data-stream or signaling-stream. The foregoing termsare utilized interchangeably in the subject specification and relateddrawings. Likewise, the terms “access point,” “node B,” “base station,”“evolved Node B,” “cell,” “cell site,” and the like, can be utilizedinterchangeably in the subject application, and refer to a wirelessnetwork component or appliance that serves and receives data, control,voice, video, sound, gaming, or substantially any data-stream orsignaling-stream from a set of subscriber stations. Data and signalingstreams can be packetized or frame-based flows. It is noted that in thesubject specification and drawings, context or explicit distinctionprovides differentiation with respect to access points or base stationsthat serve and receive data from a mobile device in an outdoorenvironment, and access points or base stations that operate in aconfined, primarily indoor environment overlaid in an outdoor coveragearea. Data and signaling streams can be packetized or frame-based flows.

Furthermore, the terms “user,” “subscriber,” “customer,” “consumer,” andthe like are employed interchangeably throughout the subjectspecification, unless context warrants particular distinction(s) amongthe terms. It should be appreciated that such terms can refer to humanentities, associated devices, or automated components supported throughartificial intelligence (e.g., a capacity to make inference based oncomplex mathematical formalisms) which can provide simulated vision,sound recognition and so forth. In addition, the terms “wirelessnetwork” and “network” are used interchangeable in the subjectapplication, when context wherein the term is utilized warrantsdistinction for clarity purposes such distinction is made explicit.

Moreover, the word “exemplary” is used herein to mean serving as anexample, instance, or illustration. Any aspect or design describedherein as “exemplary” is not necessarily to be construed as preferred oradvantageous over other aspects or designs. Rather, use of the wordexemplary is intended to present concepts in a concrete fashion. As usedin this application, the term “or” is intended to mean an inclusive “or”rather than an exclusive “or”. That is, unless specified otherwise, orclear from context, “X employs A or B” is intended to mean any of thenatural inclusive permutations. That is, if X employs A; X employs B; orX employs both A and B, then “X employs A or B” is satisfied under anyof the foregoing instances. In addition, the articles “a” and “an” asused in this application and the appended claims should generally beconstrued to mean “one or more” unless specified otherwise or clear fromcontext to be directed to a singular form.

In addition, while a particular feature may have been disclosed withrespect to only one of several implementations, such feature may becombined with one or more other features of the other implementations asmay be desired and advantageous for any given or particular application.Furthermore, to the extent that the terms “includes” and “including” andvariants thereof are used in either the detailed description or theclaims, these terms are intended to be inclusive in a manner similar tothe term “comprising.”

The above descriptions of various embodiments of the subject disclosureand corresponding figures and what is described in the Abstract, aredescribed herein for illustrative purposes, and are not intended to beexhaustive or to limit the disclosed embodiments to the precise formsdisclosed. It is to be understood that one of ordinary skill in the artmay recognize that other embodiments having modifications, permutations,combinations, and additions can be implemented for performing the same,similar, alternative, or substitute functions of the disclosed subjectmatter, and are therefore considered within the scope of thisdisclosure. Therefore, the disclosed subject matter should not belimited to any single embodiment described herein, but rather should beconstrued in breadth and scope in accordance with the claims below.

What is claimed is:
 1. A first amplifier device, comprising: aprocessor; and a memory that stores executable instructions that, whenexecuted by the processor, facilitate performance of operations,comprising: sending a first output to a measurement component for afirst determination, based on the first output, of a first amplificationnonlinearity associated with the first amplifier device; receiving afirst pre-distortion signal from a pre-distorter component, wherein thepre-distorter component determined the first pre-distortion signal basedon the first amplification nonlinearity; and applying the firstpre-distortion signal to the first amplifier device, wherein the firstpre-distortion signal is further applied to a second amplifier devicefor a second determination of a second amplification nonlinearityassociated with the second amplifier device.
 2. The first amplifierdevice of claim 1, wherein the pre-distorter component further:generated a first pre-distortion coefficient based on the firstamplification nonlinearity; and determined the first pre-distortionsignal further based on the first pre-distortion coefficient.
 3. Thefirst amplifier device of claim 2, wherein the pre-distorter componentfurther generated a second pre-distortion coefficient based on thesecond amplification nonlinearity associated with the second amplifierdevice, and wherein the first pre-distortion signal is further appliedto the second amplifier device based on a third determination by themeasurement component that the first pre-distortion coefficient and thesecond pre-distortion coefficient are similar according to a similaritycriterion.
 4. The first amplifier device of claim 3, wherein thesimilarity criterion is based on a difference between the first outputof the first amplifier device and a second output of the secondamplifier device.
 5. The first amplifier device of claim 3, wherein themeasurement component: sampled the first output of the first amplifierdevice and a second output of the second amplifier device at definedintervals; and based on the sampling, evaluated the similarity criterionbetween an updated first pre-distortion coefficient, resulting from afirst update of the first pre-distortion coefficient, and an updatedsecond pre-distortion coefficient, resulting from a first update of thefirst pre-distortion coefficient, to maintain application of the firstpre-distortion signal to the second amplifier device for the secondamplification nonlinearity.
 6. The first amplifier device of claim 3,wherein the measurement component further sampled the first output ofthe first amplifier device and a second output of the second amplifierdevice, in response to a change in an environmental condition.
 7. Thefirst amplifier device of claim 3, wherein the similarity criterionbetween the first pre-distortion coefficient and the secondpre-distortion coefficient comprises a comparison of a similaritybetween the first pre-distortion coefficient and the secondpre-distortion coefficient to a threshold value.
 8. The first amplifierdevice of claim 7, wherein the measurement component further: measuredan adjacent channel leakage ratio associated with the first amplifierdevice and the second amplifier device; and set the threshold value tobe a highest value of a group of values that results in the adjacentchannel leakage ratio being below a predetermined value.
 9. The firstamplifier device of claim 1, further comprising, receiving a baselinesignal from the measurement component, and wherein the measurementcomponent determined the first amplification nonlinearity associatedwith the first amplifier device further based on the baseline signal.10. A method, comprising: identifying, by a transmitter devicecomprising a processor, a first digital pre-distortion coefficient of afirst power amplifier; identifying, by the transmitter device, a seconddigital pre-distortion coefficient of a second power amplifier, whereinthe first digital pre-distortion coefficient and the second digitalpre-distortion coefficient are respectively associated with a firstpower amplification nonlinearity associated with the first poweramplifier and a second power amplification nonlinearity associated withthe second power amplifier; determining, by the transmitter device, thatthe first digital pre-distortion coefficient and the second digitalpre-distortion coefficient are similar according to a similaritycriterion; and applying, by the transmitter device, a firstpre-distortion signal respectively to the first power amplifier and thesecond power amplifier based on the first digital pre-distortioncoefficient and the second digital pre-distortion coefficient.
 11. Themethod of claim 10, further comprising, sampling, by the transmitterdevice, the first power amplifier and the second power amplifier atdefined intervals to determine whether the first digital pre-distortioncoefficient and the second digital pre-distortion coefficient remainsimilar according to the similarity criterion.
 12. The method of claim10, further comprising, in response to determining that the firstdigital pre-distortion coefficient and the second digital pre-distortioncoefficient are no longer similar according to the similarity criterion,and in response to determining that the second digital pre-distortioncoefficient is similar according to the similarity criterion of a thirddigital pre-distortion coefficient associated with a third poweramplifier, applying, by the transmitter device, a second pre-distortionsignal respectively to the second power amplifier and the third poweramplifier based on the second digital pre-distortion coefficient and thethird digital pre-distortion coefficient.
 13. The method of claim 10,further comprising, sampling, by the transmitter device, the first poweramplifier and the second power amplifier in response to a change in anenvironmental condition.
 14. The method of claim 10, wherein theidentifying the first digital pre-distortion coefficient and theidentifying the second digital pre-distortion coefficient are based onrespective outputs of the first power amplifier and the second poweramplifier measured in response to sending a baseline signal to the firstpower amplifier and the second power amplifier.
 15. The method of claim10, wherein the similarity criterion is based on a cost function of adifference between a first output of the first power amplifier and asecond output of the second power amplifier.
 16. The method of claim 15,further comprising, determining, by the transmitter device, that thefirst digital pre-distortion coefficient and the second digitalpre-distortion coefficient are no longer similar in response to thedifference being determined to be above a threshold value, the firstdigital pre-distortion coefficient and the second digital pre-distortioncoefficient.
 17. The method of claim 10, wherein the determining thatthe first digital pre-distortion coefficient and the second digitalpre-distortion coefficient are similar comprises determining the firstdigital pre-distortion coefficient and the second digital pre-distortioncoefficient are similar in response to a difference between respectiveoutputs of the first power amplifier and a second amplifier device beingdetermined to be below a threshold value.
 18. The method of claim 17,further comprising: measuring, by the transmitter device, an adjacentchannel leakage ratio associated with the first power amplifier and thesecond power amplifier while concurrently adjusting the threshold value;and setting, by the transmitter device, the threshold value to be ahighest value of a group of values that results in the adjacent channelleakage ratio being below a predetermined value.
 19. A non-transitorymachine-readable medium, comprising executable instructions that, whenexecuted by a processor of a first amplifier device, facilitateperformance of operations, comprising: transmitting a first output to ameasurement device, wherein the measurement device determined a firstamplification nonlinearity associated with the first amplifier device,based on the first output; and receiving a first pre-distortion signalfrom a pre-distorter device for application to the first amplifierdevice, wherein the pre-distorter device: determined that the firstpre-distortion signal is based on the first amplification nonlinearity;and applied, based on a criterion, the first pre-distortion signal to asecond amplifier device for a second amplification nonlinearityassociated with the second amplifier device.
 20. The non-transitorymachine-readable medium of claim 19, wherein the operations furthercomprise receiving a baseline signal from the measurement device, andwherein the measurement device further determined the firstamplification nonlinearity associated with the first amplifier device isbased on the baseline signal.